A remediation process for the insulation of high-voltage electrical power cables requires the injection of a remediation fluid into the cables. It is known in the art that remediation fluids which are most effective have viscosities less than 50 centistokes at 25° C. as these fluids must be able to flow through very small interstitial spaces over very long cable lengths and must be of small enough molecular size to diffuse into the cable insulation. In many instances, this injection process takes place while the cable is energized. When the remediation process is performed on energized cables, a class of special cable end terminations is typically used. These terminations are known as injection elbows. Injection elbows are similar to industry standard elbow-type connectors except that special ports have been designed into them to allow for the attachment of an injection plug to the elbows.
After injection of the remediation fluid is complete, the injection plug is withdrawn from the injection port and is replaced with a sealing plug. Between the time that the injection plug is removed, and the sealing plug is installed, the injection port is open, and the energized conductor of the cable is exposed. Because of the remediation fluid's low viscosity it is likely to empty out of the open injection port. Although there is no direct electrical connection between the conductor and the grounded exterior of the cable elbow, there is the danger of an indirect electrical connection being established between the conductor and the grounded exterior of the elbow.
One such indirect pathway may be formed by contaminants that have become entrained in the remediation fluid. Contaminated fluid can be drawn from the injection port as the injection plug is withdrawn or may simply flow out under the force of gravity, thereby creating partial discharging or even a complete conductive pathway to the ground plane.
A second indirect pathway is created by source molecules such as those found in low viscosity remediation fluid, water or other contaminants which may be present in the conductor. Source molecules, also referred to as particles, can ionize or form an aerosol, which may become charged in the high-voltage field. These ionized or charged particles may then accelerate towards the ground plane creating a dynamic and conductive aerial pathway.
These two known conductive pathways, as well as any other conductive pathway established between the conductor and the ground plane, can degrade or destroy the injection elbow. Therefore, a need exists to create a barrier to block the conductive pathway between the conductive portion of the cable and the ground plane to increase the life expectancy of the injection elbow.